Telescopic drill rod

Abstract

A telescopic drill rod (2) has at least two rod members (20, 30} disposed coaxially to one another, with the inner rod member (30) being axially slidable relative to the cater rod member (20) in a telescoping mariner between an extended position and a retracted position. Both the inner rod member (30) and outer rod member (20) are equipped with joints at each end for connection, to a drill head and/or another section of drill pipe. The joints also lock the inner and outer rod members in either the extended of retracted positions, and this is accomplished with a unique frusto-conical threaded engagement that is well-suited for transmitting pressure forces.

Claims

1. A telescopic drill rod, comprising two or more rod members at least including: an inner rod member including, a first hollow tubular section of uniform cross-section along its length, a first connector attached distally at one end of said first hollow tubular section, said first connector comprising a double-male joint formed with two externally-screw-threaded surfaces separated from each other by a medial collar, and a second connector attached distally at another end of said first hollow tubular section, said second connector comprising a single-female joint formed with a receptacle open outward and away from said first hollow tubular section and having an internally-screw-threaded surface; and an outer rod member including, a second hollow tubular section having a uniform internal channel conforming to said medial collar and configured for slidable reciprocation therein, a third connector attached distally at one end of said second hollow tubular section, said third connector comprising a double-female joint formed with opposing receptacles each having an internally-screw-threaded surface, and a fourth connector attached distally at another end of said second hollow tubular section, said fourth connector comprising a single-female joint formed with a receptacle having an internally-screw-threaded surface, whereby said inner rod member and said outer rod member may be telescopically extended and secured together in a fully-extended position and retracted and secured together in a fully-retracted position, and in said fully-retracted position present constant exterior shape and dimensions along an entire length of said outer telescopic drill rod.

2. The telescopic drill rod according to claim 1, wherein said inner rod member further comprises a hollow cylindrical section of uniform diameter and a central passage passing entirely through said inner rod including said first connector and said second connector.

3. The telescopic drill rod according to claim 2, wherein said outer rod member further comprises a hollow cylindrical section of uniform diameter.

4. The telescopic drill rod according to claim 3, wherein in said fully-retracted position said inner rod member and outer rod member together present a constant exterior profile along an entire length of said telescopic drill rod.

5. The telescopic drill rod according to claim 1, wherein the two externally-screw-threaded surfaces of the first connector double-male joint are tapered.

6. The telescopic drill rod according to claim 1, wherein the two externally-screw-threaded surfaces of the first connector double-male joint are non-tapered.

7. The telescopic drill rod according to claim 1, wherein the internally-threaded receptacle of the second connector single-female joint of the inner rod member is tapered.

8. The telescopic drill rod according to claim 1, wherein the internally-threaded receptacle of the second connector single-female joint of the inner rod member is non-tapered.

9. The telescopic drill rod according to claim 1, wherein the internally-threaded receptacles of the third connector double-female joint of the outer rod member are tapered.

10. The telescopic drill rod according to claim 1, wherein the internally-threaded receptacles of the third connector double-female joint of the outer rod member are non-tapered.

11. The telescopic drill rod according to claim 1, wherein the internally-threaded receptacle of the fourth connector single-female joint of the outer rod member is tapered.

12. The telescopic drill rod according to claim 1, wherein the internally-threaded receptacle of the fourth connector single-female joint of the outer rod member is non-tapered.

13. A telescopic drill rod, comprising two or more rod members at least including: an inner rod member and an outer rod member axially slidable relative to each other in a telescoping configuration, said inner rod member further comprising an elongate hollow cylindrical section of uniform diameter along a majority of its length and extending to a double-male joint formed as a bulbous distal tip and shaped with two frusto-conical surfaces separated by a medial collar, and a single-female joint having a female frusto-conical receptacle mounted on another end of said cylindrical section, said outer rod member further comprising a hollow cylinder having a single-female joint formed with a frusto-conical receptacle at one end of said hollow cylinder, and double-female joint formed with opposing frusto-conical receptacles at another end of said hollow cylinder, whereby said inner and outer members may be coupled together in a retracted and/or extended position, and in said fully-retracted position together present a constant exterior profile along an entire length of said telescopic drill rod.

14. The telescopic drill rod according to claim 13, further comprising a central passage passing entirely through said inner rod including said first connector and said second connector, and said outer rod including said third connector and fourth connector.

15. The telescopic drill rod according to claim 14, wherein said inner rod further comprises a hollow cylindrical section of uniform diameter and the single female joint of said second connector comprises a receptacle open outward and away from said first hollow cylindrical section.

16. The telescopic drill rod according to claim 15, wherein said outer rod member further comprises a hollow cylindrical section of uniform diameter.

17. The telescopic drill rod according to claim 16, wherein in said fully-retracted position said inner rod and said outer rod combine to present a constant exterior profile along an entire length of said telescopic drill rod.

18. The telescopic drill rod according to claim 14, wherein all of said male and female locking joints include screw-threaded surfaces.

19. The telescopic drill rod according to claim 18, wherein all of said screw-threaded surfaces are tapered.

20. The telescopic drill rod according to claim 18, wherein all of said screw-threaded surfaces are non-tapered.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Other objects, features, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiment and certain modifications thereof, in which:

(2) FIG. 1 is a side cross-Section of a telescopic drill rod 2 in its unsecured intermediate position according in an embodiment of the invention with enlarged insets of some components.

(3) FIG. 2 shows the telescopic drill rod 2 secured in its fully-retracted position.

(4) FIG. 3 shows the telescopic drill rod 2 secured in its fully-extended position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(5) The present invention is a telescopic drill rod comprising two or more rod members: at least including an inner rod member and an outer rod member axially slidable relative to each other in a telescoping configuration between an extended position and a retracted position.

(6) FIG. 1 is a side cross-section of a telescopic drill rod 2 according to an embodiment of the invention shown in an intermediate (unsecured) position. The telescopic drill rod generally comprises the inner rod member 30 and outer rod member 20, inner rod member 30 being slidably carried in telescoping manner within the outer rod member 20. The inner rod member 30 can be secured in a fully retracted position (shown and described below with reference to FIG. 2), unsecured as shown in FIG. 1 for free telescoping extension or retraction, or fully extended and secured in the fully extended position (shown and described below with reference to FIG. 3).

(7) The inner rod member 30 further comprises an elongate hollow pipe section 32 of uniform or variable cross-section D1 extending from one end to an enlarged double-male joint 34 at the other end. Section 32 preferably has a uniform cross-section along its length symmetric about a central axis, and subject to that constraint may be cylindrical, hexagonal, octagonal or otherwise. As seen in the enlarged center inset to FIG. 1 double-male joint 34 comprises a bulbous distal tip shaped with two threaded surfaces 33A, 33B separated by a raised medial collar 35 of diameter D2. In the preferred embodiment both threaded surfaces 33A, 33B are oppositely tapered as shown, in which case the two threaded surfaces 33A, 33B comprise frusto-conical shapes tapering away from collar 35 with surfaces screw-threaded along their lengths. The frusto-conical shape provides a wedging effect. However, one skilled in the art will understand that non-tapered threads are suitable, in which case the case the two threaded surfaces 33A, 33B are of uniform cross-section comprising cylindrical shapes with surfaces screw-threaded along their lengths. In either case the collar 33 is of slightly greater diameter D2 than the largest threads of surfaces 33A, 33B and presents a smooth flat surface to serve as a bushing for slidable engagement with the inner surface of outer rod member 20. The smallest threads of surfaces 33A, 33B are of slightly greater width/diameter D1 than the hollow pipe section 32.

(8) The inner rod member 30 extends to another single-female joint 36 mounted on the other end. Single female joint 36 comprises a thicker cylindrical section of uniform exterior dimension formed with a cylindrical receptacle 39 on one end of diameter slightly larger than D2 for a compression and/or screw-threaded fit with cylindrical section 32. The outer face of single-female joint 36 is formed with a screw-threaded receptacle (again, tapered-conical or non-tapered threads) opening outward to an aperture. The receptacle of single-female joint 36 is shaped, dimensioned and threaded for screw-insertion of a conventional drill head (not shown) or, alternatively, for screw-insertion of another inner rod member 30.

(9) The outer rod member 20 comprises an elongate hollow cylinder 22 of inner diameter D3 slightly greater than D2 of collar 33 for slidable insertion of the double-male joint 34 of inner rod member 30. The leftmost end of the outer rod member 20 is equipped with a single-female joint 24 compression and/or screw-threaded into the end of cylinder 22. Single-female joint 24 is a thicker cylindrical section having a two-tier exterior dimension for flush insertion into the cylinder 22. The inner face of single-female joint 24 is formed with a threaded receptacle (again, tapered-conical or non-tapered threads) opening inward from an aperture to a through-bore of diameter D1. Where tapered threads are used, the receptacle of the inner face of single-female joint 24 is frusto-conical, and the frusto-conical receptacle of single-female joint 24 is shaped, dimensioned and threaded to conform to the innermost frusto-conical threaded surface 33A of the double-male joint 34 of inner rod member 30 for screw-insertion therein. However, one skilled in the art will understand that non-tapered threads are suitable, in which case the case the threaded surface of the receptacle of the inner face of single-female joint 24 is of substantially uniform cross-section with non-tapered threads. The through-bore through single-female joint 24 continues outward through the outer face of single-female joint 24, and the through-bore may or may not be internally grooved for holding a rubberized rod wiper 25, e.g., an O-ring or other such wiping device or mechanism captive therein where wiping might be of advantage to the drilling. The rod wiper 2 squeegees the inner rod member 30 clean as is slides through.

(10) The other end (rightward) of the outer rod member 20 is equipped with a double-female joint 26 that is compression and/or screw-threaded into the end of cylinder 22. Double-female joint 26 is a thicker cylindrical section having a two-tier exterior dimension for flush insertion into the cylinder 22. The inner (leftmost) face of double-female joint 26 is formed with an inner cylindrical lip 27 having a diameter slightly more than D2, lip 27 opening inward to a threaded receptacle 29 shaped, dimensioned and threaded to conform to the outermost threaded surface 33B of the double-male joint 34 of inner rod member 30 for screw-insertion therein. Once more, tapered-conical or non-tapered threads may be used. Where tapered threads are used as shown, the receptacle 29 of double-female joint 26 is frusto-conical, and the frusto-conical receptacle 29 of double-female joint 26 is shaped, dimensioned and threaded to conform to the outermost frusto-conical threaded surface 33B of the double-male joint 34 of inner rod member 30 for screw-insertion therein. However, one skilled in the art will understand that non-tapered threads are suitable, in which case the case the threaded surface of the receptacle of the receptacle of double-female joint 26 is of uniform cross-section. The outer (rightmost) face of double-female joint 26 is likewise formed with a non-tapered (uniform) or tapered (frusta-conical) threaded receptacle 23. A tapered threaded receptacle 23 is illustrated in FIG. 1 with a diameter tapering outward to an aperture of slightly more than D2.

(11) The length of outer rod member 20 is L1, and inner rod member 30 is L2, giving a sum component length of L1+L2. However, it should now be apparent that the invention makes it possible for the inner and outer members 30, 20 of the telescopic drill rod 2 may be securely coupled together in the retracted and/or extended position by screw-insertion, without aid from further devices, in a simple, convenient manner. The present configuration optimizes both extension and retraction without compromising strength and security when locked in either the fully extended or fully retracted position.

(12) FIG. 2 shows the telescopic drill rod 2 in its fully-retracted position with the double-male joint 34 of inner rod member 30 screw-inserted into the leftmost receptacle of the double female joint 26 of outer rod member 20. In this position the total length L3 is greater than L1 by about the length of single-male receptacle 36.

(13) FIG. 3 shows the telescopic drill rod 2 in its fully-extended position with the double-male joint 34 of inner rod member 30 screw-inserted into the female receptacle of the single female joint 24 of outer rod member 20. In this position L3 is slightly less than L1+L2 by a bit more than the length of double-male joint 34.

(14) Having now fully set forth the preferred embodiments and certain modifications of the concept underlying the present invention, various other embodiments as well as certain variations and modifications of the embodiments herein shown and described will obviously occur to those skilled in the art upon becoming familiar with said underlying concept. It is to be understood, therefore, that the invention may be practiced otherwise than as specifically set forth in the appended claims.

STATEMENT OF INDUSTRIAL APPLICABILITY

(15) Large hole drilling application's sometimes use Kelly drills that employ telescopically extendable drill attachments, allowing Kelly rod attachments to be added down the hole. However, there are numerous construction applications that require small-hole drilling including anchor drilling, micropiles, soil nailing, water wells and jet grouting, and other such smaller hole drilling. While conventional Kelly drilling is good for larger holes and rocky formations it is not well-suited for tieback (micropile) drill rigs and other small hole drilling rigs. There would be great industrial applicability in a telescopically extendable drill rod more suitable for use with tieback drill rigs (alternately known as micropile drill rigs) suitable for use in small-hole drilling.